Spark plug cleaner



july l5, E952 T. G. MCDOUGAL 'E1-AL 2,603,045 SPARK PLUG CLEANER iled Juge 16, 1949 Patented July 15, 1952 UNITED STATES PATENT; ormai:l

- ASPARK PLUG CLEANER Taine G. McDougal and Earl W. Pierce, Flint,

Mich.,'assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application June 16, 1949, Serial No. 99,570

This invention relates to a cleaning and polishing tool used in conjunction with an' abrasive. and especially a cleaning tool for the terminal Well of aircraft spark plugs.

'I'his cleaning tool consists of a cylindrical rubber body with helical threads or grooves on the external surface and internal supporting and clamping means to rotate the tool. The internal surface of the well of the spark plugs is cleaned by employing an abrasive paste or suspension between the said surface and the rotating tool and causing the abrasive to move between the tool and the work to clean or polish the work.

The object of this invention is to provide a rotary cleaning and polishing tool formed with rubber and having helical threads to distribute an abrasive cleaning or polishing compound.

Another object of this invention is to provide a cylindrical rubber cleaning and polishing tool having a central support and securing member for rotatably driving the tool and for expanding the tool.

Another object of the invention is to provide a support for rotatably driving the rubber cleaning tool and holding the tool so that it may be conveniently replaced when worn. Y

These and other objects will be apparent from the following drawings and specifications.

Figure 1 is an elevation in partial cross sec- 12 claims. (C1. 51--19oi through the rubber cleaningto'o'l. lThe supporting core has a frustro-conical portion 22 adjacent the face I8 and a cylindrical end portion. The rubber cleaning tool 26 has a central bore 28 with a frustro-conical portion and a cylindrical portion complementary to the core 20, and is fitted over the core with the enlarged shank portion 32 abutting against the face I8.

The main portion of thecylindrical cleaning tool 26 has a helical thread 34'for'med therein to distribute the abrasive, and one or moreaxial grooves 36 extending the` full length of the threaded portion of the cleaning tool to vallow the air to escape when the tool is inserted in a spark plug Well 98. The enlarged shank portion of the cleaning tool has a cylindrical section and a tapered or frustro-conical section 3B to provide an anchorage. A

The cleaning tool 26 is held and clamped on the support .by means of a cylindrical clamping sleeve 42, which is threaded on ,the enlarged cylindrical portionl I6. of the support. The clamping sleeve has an internaltapered surface 44 at one end, which is complementary to the tapered surface 38 .on the cleaning tool. After y the cleaning tool 26 is 4LOOStioned on the support tion of the cleaning tool positioned on a drive shaft and in a spark plug well.

Figure 2 shows a partial perspective view of the rubber cleaning tool.

Figure 3 is a partial view of a tool.

Figure 4 is a partial perspective view showing the shank of the modified cleaning tool.

Figure is a view in partial section of a modiiication having attaching means such as a chuck or sleeve.

This cleaning tool is rotatably driven by attaching it to a driven shaft. The attaching means may be a chuck or sleeve,v .or a bore in the end of the shaft I0 vwith ka set-screw or keyway (not shown) to securethe tool therein. The tool consists of a .main .supportingelement I2 havinga stem portion I'Iltting into Vthe bore modified cleaning Vfor securing it to the shaft, and a central env larged coaxial cylindrical'portion"16. The surface of the cylindrical portior'i 15 is threaded, and the front face has a flat' annular portion I8 to provide support for the rubber portion of the tool. A supporting core 20, coaxial with the cylindrical portion and extending from the center of the annular face I8 extends partially I2, the sleeve 42 is positioned on thetool and threaded on the support. The sleeve engages the tapered and cylindrical sections of the shank 32 to compress and hold the shank against the frustro-conical portion 22. e Y

In a modified formof the invention a similar supporting member I2 is employed having a shank I4 and a core 20. Thecleaning tool 26 is similarly threaded throughout the cylindrical portion, but the shank 52 has flat sides 54 and a fiat front face 56. The modified clamping sleeve 58 is threaded to secure it to the enlarged cylindrical portion of the support and has 'a square cavity 62 at the forward end with flat side walls and a flat front wall complementary to the squared end of the shank 52.

The spark plug 96 having a Well 98 is the type generally employed on aircraft. Following a certain period of service it has been found that an adherent deposit forms on the interior surface of the well 98. In order toremov'e this4 deposit it has been found necessary to employ a cleaning process similar in some respects to a polishing or lapping operation, while atthesame time applying a solvent to loosen the organic bond of the deposit and to aid in removing any oily or greasy constituents. The rubber cleaning tool, which is about the same diameter as the internal diameter of the spark plug Well, is coated with-cleaning compound and inserted in the spark plug well.

The cleaning tool is then rotated to clean deposit from the interior of the spark plug by the abrading action of the cleaning compound. The rotary action of the tool and the helical threads continuously move the cleaning compound over the surfaces.

The other typeY of cleaning't'oolillustrated in Figure fis expandable Vin order toadjus't the diameter of the tool for wear. The tool has a cylindrical stem 64, which is attached in any suitable manner to a rotating shaft to drive orrotate the tool. A bore 66 in the outer end of the stern slidably receives a tapered support 66' having a A medium firm rubber compound, which preferably has a hardness of 50 to 70 on the Shore durometer is compounded to resist softening by the solvent content of the cleaning compound.

Though certain specific embodiments of the invention have been shown for the purpose of illustration, the invention is capable of various modifications within vthe scope of the claims.

We claim:

1. A tool having a stem member for connecting to a driven shaft, said stem having a threaded enlarged portion, a support portion fixed to and projecting axially from said enlarged portion, said full sized cylindrical portion-10 which slida'bly iits in the bore 66 without play. A flat 1I vis provided on the portion 1D. The support is secured.

in any set position by the set-screw 12 engaging the fiat 1|. The support 66 has the inner end section 10 of uniform diameter, a tapered center section '16 and an outer section i8 of uniform diameter the same as section l0. lA cylindrical rubber tool 60 with similar helical threads 82 and a longitudinal groove similar to groove, 36 has a central bore 84 with a tapered section and a cylindrical section similar to the tapered ,section 16 and the outer section 18 of the support. Complementary keyways 86 in thesuppcrt, 63V in the rubber tool and 90 in the stem 64 provide a seat for key 92, whichlprevents rotation of the rubber tool relativeto the support. This expandable tool is usedto clean or .polis an internal bore in the same manner as the above described tools. However, when the rubber wears due to the abrasive action, the rubber element may be expanded to its former diameter by loosening the set-screw .12 and .moving or driving the support 68 inward. The coa'ction of the complementary tapered surface ontheA support and the tapered surface on the inside of the rubber tooll will expand the tool.` I t will be appreciated that the tapered surfaces may extend for the full length of the rubber tool.

The cleaning compound is made of a fine abrasive material and a good solvent for the' organic binders of the deposits toge'ther with'v vnaterial to maintain the abrasive in suspension in the solvent constituent. It is preferred to use suiiicient abrasive andsuspending medium to form a thick paste which facilitates application to the rubber tool. Though the .composition of vthe cleaning compound may be varied, we have successfully used a composition having by weight 52% of a powdered feldspar and 6% of 9% Water suspension of bentonite and 42% of diethylene glycol monobutyl ether, A suitable cleaning compound may be made having the following ingredients within the specified ranges of percentages:

Bentonite Water 2.8 to 23.0 Feldspar 40.0 to 65.0 Solvent Balance enlarged portion providing an annular seat surrounding saidv support, a rubber member having an axial bore fitting over said support portion and a shank portion abutting said annular portion of said enlarged portion, a screw threaded ferrule positioned over said rubber member and threaded on said threaded enlarged portion to clamp the shank portion of the rubber member against the enlarged portion of the stem.,

2. The invention defined by claim 1, said shank portion having a partial conical portiornand said ferrule having a complementary internal conical portion. Y

3. The invention defined by claim 1,-said shank portion having a non-round section` and said ferrule having a complementary internal opening. l

4. A tool having a stem with a boreY in one end, a'support adjustably slidably-mounted in said bore and having a tapered portion projecting from said stem, a round rubber member having a similarly tapered bore positioned on said support, so that axial movement of said support will expand said rubber element, a key in said support and rubber member to prevent relative rotation. y

5. In a tool for applying an abrasive cleaning and polishing compound, a cylindrical rubber member, means to rotate said member about an axis, said member, having a helical groove in the surfacev about said axis to distribute the abrasive compound over the work surface, and an axial groove to allow air to escape when thetool is inserted in a bore and to assist in distributing the abrasive compound. Y

6. In a cleaning tool for applying an abrasive cleaning and polishing compound, a stem having a bore and an end face surrounding said bore,v a cylindrical rubber cleaning element having a central bore, a supporting 'element adjustably Y secured-in said bore in the stem and having a Though polyglycols and their monoy or diethers are preferred due to their water solubility, other solvents, such as naphtha, benzene, carbon tetrachloride and chloroform, maybe used.`

The feldsparpreferably should have a particle size as defined below:

Per cent Over 40 microns 0.5 to" 1.5

portion positioned in said bore in said rubber element, cooperating tapered portions on said support and said rubber element to expand said rubber element, said rubber element having an end face engaging the end face of'th'e stem, and an angular groove on said cylindrical rubber cleaning element to distribute the abrasive-compound over the work surface.

v7. In a tool having astem member for connecting the tool to adi-iven 4shaft, saidstem having a thre'adedfenlarged porticnyathinner support Aportion fixed Ito ,and projecting axially fromsaid enlarged portion, saidenlrgedfportion providing an annular'seat.surroundingosaid support, arubber member having an raxial bore fitting over-said support portion `and a shank portion abutting said annular-seat of saidaenlarged portion, and a screw-threaded ferrule positioned over said rubber member and;;threaded ,on said threaded enlarged portion toclamp Athe 'shank portion of the rubber member against said annular seat of the stem.

8. In a tool having a stem member for connecting the tool to a driven shaft, said stem. having a threaded enlarged portion, a thinner support portion xed to and projecting axially from said enlarged portion, said enlarged portion providing an annular seat surrounding said support, a rubber member having an axial bore tting over said support portion, a thin working portion and a thicker shank portion abutting said annular seat of said enlarged portion, and a screw threaded ferrule positioned over said rubber member and threaded on said threaded enlarged portion to clamp the shank portion of the rubber member against said annular seat of the stem.

9. In a tool having a stem member for connecting the tool to a driven shaft, said stem having a threaded enlarged portion, a thinner support portion xed to and projecting axially from said enlarged portion, said enlarged portion providing an annular seat surrounding said support, a rubber member having an axial bore fitting over said support portion, a thin cylindrical portion coaxial with said bore and a thicker shank portion abutting said annular seat of said enlarged portion, a shoulder between said cylindrical portion and said shank portion, and a screw threaded ferrule having a ilange at one end positioned over said rubber member and threaded on said threaded enlarged portion, said flange on the ferrule engaging said shoulder to clamp the shank portion of the rubber member against said annular seat of the stem.

10. A tool having a stem with a bore in one end, asupport slidably mounted in said bore and having a tapered portion projecting from said stem, means to secure said support in adjusted position on said stem, a rubber member having a similarly tapered bore positioned on said support so that axial movement of said support will expand said rubber element, and means to prevent relative rotation between said support and rubber member.

11. A tool for cleaning and polishing including; a cylindrical resilient rubber compound member, means to rotate said member about an axis, said member having grooves in the surface thereof lying at an oblique angle to said axis to apply REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 899,626 Schultz Sept. 29, 1908 987,959 Coney Mar. 28, 1911 1,150,024 Ford Aug. 1'7J 1915 1,620,990 Brothers Mar. 15, 1927 1,725,002 Jenkins Aug. 20, 1929 

